اسم المؤلف
Theodore Wildi
التاريخ
8 نوفمبر 2022
التصنيف
المشاهدات
424
التقييم

Electrical Machines, Drives, and Power Systems
Fifth Edition
Theodore Wildi
Professor Emeritus, Laval University
Contents
PART I. FUNDAMENTALS

1. UNITS 3
1 .0 Introduction 3
2. 1 Systems of units 3
1.2 Getting used to SI 4
1 .3 Base and derived units of the SI 4
1.4 Definitions of base units 5
1.5 Definitions of derived units 5
1 .6 Multiples and submultiples
of SI units 7
1.7 Commonly used units 7
1 .8 Conversion charts and their use 8
1 .9 The per-unit system of
measurement 9
I. IO Per-unit system with one base 10
3. 1 1 Per-unit system with two bases ll
Questions and Problems 1 2
4. FUNDAMENTALS OF ELECTRICITY,
MAGNETISM, AND CIRCUITS 15
2.0 Introduction 15
5. 1 Conventional and electron current
flow 1 5
2.2 Distinction between sources and
2.3 Sign notation 1 7
2.4 Double-subscript notation for
voltages 1 7
2.5 Sign notation for voltages 17
2.6 Graph of an alternating voltage 18
2.7 Positive and negative currents 19
2.8 Sinusoidal voltage 1 9
2.9 Converting cosine functions into sine
functions 20
2.10 Effective value of an ac voltage 20
6. 1 1 Phasor representation 2 1
7. 1 2 Harmonics 23
8. 1 3 Energy in an inductor 25 –
2.14 Energy in a capacitor 25
9. 15 Some useful equations 26 A
ELECTROMAGNETISM JV.y ^7
10. 16 Magnetic field intensity /7 and
11. 17 B-H curve of vacuum 27
12. 18 B-H curve of a magnetic material’ 27
13. 1 9 Determining the relative BiSuiOAk
permeability 28viii CONTENTS
2.20 Faraday’s law of electromagnetic 3.9 Kinetic energy of rotation, moment of
induction 29 inertia 54
2.21 Voltage induced in a conductor 30 3.10 Torque, inertia, and change in
2.22 Lorentz force on a conductor 3 1 speed 57
2.23 Direction of the force acting on a 3.11 Speed of a motor/load system 57
straight conductor 3 1 3.12 Power flow in a mechanically coupled
2.24 Residual flux density and coercive system 58
force 32 3.13 Motor driving a load having inertia 58
2.25 Hysteresis loop 33 3.14 Electric motors driving linear motion
2.26 Hysteresis loss 33 loads 59
2.27 Hysteresis losses caused by 3.15 Heat and temperature 60
rotation 33 3.16 Temperature scales 6 1
2.28 Eddy currents 34 3.17 Heat required to raise the temperature
2.29 Eddy currents in a stationary iron of a body 61
core 35 3.18 Transmission of heat 62
2.30 Eddy-current losses in a revolving 3.19 Heat transfer by conduction 62
core 35 3.20 Heat transfer by convection 63
2.31 Current in an inductor 36
CIRCUITS AND EQUATIONS
3.21 Calculating the losses by
convection 63
3.22 Heat transfer by radiation 64
2.32 Kirchhoff’s voltage law 40 3.23 Calculating radiation losses 64
2.33 Kirchhoff’s voltage law and double¬
subscript notation 40
Questions and Problems 65
2.34 Kirchhoff’s current law 41
PART II. ELECTRICAL MACHINES AND
2.35 Currents, impedances, and associated
voltages 41 TRANSFORMERS
2.36 Kirchhoff’s laws and ac circuits 43
2.37 KVL and sign notation 43 4. DIRECT-CURRENT GENERATORS 71
2.38 Solving ac and de circuits with sign 4.0 Introduction 7 1
notation 44 4. 1 Generating an ac voltage 7 1
2.39 Circuits and hybrid notation 45 4.2 Direct-current generator 72
Questions and Problems 46 4.3 Difference between ac and de
generators 73
FUNDAMENTALS OF MECHANICS 4.4 Improving the waveshape 73
AND HEAT 50 4.5 Induced voltage 75
3.0 Introduction 50 4.6 Neutral zones 76
3.1 Force 50 4.7 Value of the induced voltage 76
3.2 Torque 5 1 4.8 Generator under load: the energy
3.3 Mechanical work 51 conversion process 77
3.4 Power 52 4.9 Armature reaction 77
3.5 Power of a motor 52 4.I0 Shifting the brushes to improve
3.6 Transformation of energy 53 commutation 78
3.7 Efficiency of a machine 53 4. II Commutating poles 79
3.8 Kinetic energy of linear motion 54 4. 1 2 Separately excited generator 79CONTENTS ix
14. 13 No-load operation and saturation
curve 79
4.14 Shunt generator 80
4.15 Controlling the voltage of a shunt
generator 81
4.16 Equivalent circuit 82
4.17 Separately excited generator under
4.18 Shunt generator under load 83
4.19 Compound generator 83
4.20 Differential compound generator 84
4.22 Generator specifications 84
CONSTRUCTION OF DIRECT-CURRENT GENERATORS
4.23 Field 84
4.24 Armature 85
4.25 Commutator and brushes 86
4.26 Details of a multipole generator 88
4.27 The ideal commutation process 91
4.28 The practical commutation process 92
Questions and Problems 93
15. DIRECT-CURRENT MOTORS 96
5.0 Introduction 96
5.1 Counter-electromotive force
(cemf) 96
5.2 Acceleration of the motor 97
5.3 Mechanical power and torque 98
5.4 Speed of rotation 100
5.5 Armature speed control 101
5.6 Field speed control 102
5.7 Shunt motor under load 103
5.8 Series motor 104
5.9 Series motor speed control 105
5.10 Applications of the series motor 106
5.11 Compound motor 106
5.12 Reversing the direction of rotation 107
5.13 Starting a shunt motor 108
5.14 Face-plate starter 108
5.15 Stopping a motor 109
5.16 Dynamic braking 109
5.17 Plugging 110
16. 1 8 Dynamic braking and mechanical time
constant 1 1 1
5.19 Armature reaction 113
5.20 Flux distortion due to armature
reaction 1 1 3
5.21 Commutating poles 113
5.22 Compensating winding 114
5.23 Basics of variable speed control 1 1 4
5.24 Permanent magnet motors 117
Questions and Problems 1 18
17. EFFICIENCY AND HEATING OF
ELECTRICAL MACHINES 120
6.0 Introduction 1 20
18. 1 Mechanical losses 1 20
6.2 Electrical losses 1 20
6.3 Losses as a function of load 1 23
6.4 Efficiency curve 123
6.5 Temperature rise 125
6.6 Life expectancy of electric
equipment 126
6.7 Thermal classification of
insulators 126
6.8 Maximum ambient temperature and
hot-spot temperature rise 127
6.9 Temperature rise by the resistance
method 1 29
6.10 Relationship between the speed and
size of a machine 130
Questions and Problems 1 31
19. ACTIVE, REACTIVE, AND APPARENT
POWER 134
7.0 Introduction 1 34
20. 1 Instantaneous power 1 34
7.2 Active power 1 36
7.3 Reactive power 137
7.4 Definition of reactive load and
reactive source 1 38
7.5 The capacitor and reactive
power 1 39
7.6 Distinction between active and
reactive power 140X CONTENTS
7.7 Combined active and reactive loads:
apparent power 141
8.19 Power measurement in 3-phase.
4-wire circuits 177
7.8 Relationship between P. Q. and S 141 8.20 Varmeter 177
7.9 Power factor 143 8.21 A remarkable single-phase to 3-phase
7.10 Power triangle 144 transformation 178
7.11 Further aspects of sources and
Questions and Problems 180
7.12 Systems comprising several loads 146 9. THE IDEAL TRANSFORMER 183
7.13 Reactive power without magnetic 9.0 Introduction 183
fields 148 9. 1 Voltage induced in a coil 1 83
7.14 Solving AC circuits using the power
triangle method 148
9.2 Applied voltage and induced
voltage 1 84
7.15 Power and vector notation 1 5 1 9.3 Elementary transformer 185
7.16 Rules on sources and loads (sign 9.4 Polarity of a transformer 186
notation) 154 9.5 Properties of polarity marks 186
7.17 Rules on sources and loads (double
subscript notation) 154
9.6 Ideal transformer at no-load; voltage
ratio 1 87
Questions and Problems 155 9.7 Ideal transformer under load; current
ratio 188
THREE-PHASE CIRCUITS 158 9.8 Circuit symbol for an ideal
8.0 Introduction 158 transformer 191
8.1 Polyphase systems 158 9.9 Impedance ratio 191
8.2 Single-phase generator 159 9.10 Shifting impedances from secondary
8.3
8.4
Power output of a single-phase
generator 160
Two-phase generator 160
to primary and vice versa 192
Questions and Problems 195
8.5 Power output of a 2-phase 10. PRACTICAL TRANSFORMERS 197
generator 16 1 10.0 Introduction 197
8.6 Three-phase generator 162 10.I Ideal transformer with an imperfect
8.7 Power output of a 3-phase core 1 97
generator 162 10.2 Ideal transformer with loose
8.8 Wye connection 164 coupling 199
8.9 Voltage relationships 165 10.3 Primary and secondary leakage
8.10 Delta connection 167 reactance 200
8.11 Power transmitted by a 3-phase
line 168
10.4 Equivalent circuit of a practical
transformer 202
8.12 Active, reactive and apparent power in
3-phase circuits 169
10.5 Construction of a power
transformer 203
8.13 Solving 3-phase circuits 1 70 10.6 Standard terminal markings 204
8.14 Industrial loads 171 10.7 Polarity tests 204
8.15 Phase sequence 174 10.8 Transformer taps 205
8.16 Determining the phase sequence 175 10.9 Losses and transformer rating 206
8.17 Power measurement in ac circuits 176 10.10 No-load saturation curve 206
8.18 Power measurement in 3-phase. 10.11 Cooling methods 207
3-wire circuits 176 10.12 Simplifying the equivalent circuit 209CONTENTS xi
10.13 Voltage regulation 211
10.14 Measuring transformer
impedances 212
10.15 Introducing the per unit method 215
1 0. 1 6 Impedance of a transformer 2 1 6
10.17 Typical per-unit impedances 216
10.18 Transformers in parallel 219
Questions and Problems 221
21. SPECIAL TRANSFORMERS 225
1 1 .0 Introduction 225
1 1 . 1 Dual-voltage distribution
transformer 225
1 1.2 Autotransformer 226
1 1 .3 Conventional transformer connected
as an autotransformer 228
1 1 .4 Voltage transformers 230
1 1 .5 Current transformers 23 1
1 1 .6 Opening the secondary of a CT can be
dangerous 233
1 1 .7 Toroidal current transformers 234
1 1.8 Variable autotransformer 235
1 1.9 High-impedance transformers 236
1 1. 10 Induction heating transformers 237
1 1. 1 1 High-frequency transformers 238
Questions and Problems 24 1
22. THREE-PHASE TRANSFORMERS 243
12.0 Introduction 243
1 2. 1 Basic properties of 3-phase
transformer banks 243
12.2 Delta-delta connection 244
12.3 Delta-wye connection 246
12.4 Wye-delta connection 247
12.5 Wye-wye connection 248
12.6 Open-delta connection 248
12.7 Three-phase transformers 249
12.8 Step-up and step-down
autotransformer 25 1
12.9 Phase-shift principle 253
12.10 Three-phase to 2-phase
transformation 254
1 2. 1 1 Phase-shift transformer 256
12.12 Calculations involving 3-phase trans¬
formers 258
12.13 Polarity marking of 3-phase
transformers 260
Questions and Problems 260
23. THREE-PHASE INDUCTION
MOTORS 263
1 3.0 Introduction 263
1 3. 1 Principal components 263
1 3.2 Principle of operation 264
13.3 The rotating field 265
1 3.4 Direction of rotation 270
1 3.5 Number of poles-synchronous
speed 27 1
1 3.6 Starting characteristics of a squirrel¬
cage motor 273
1 3.7 Acceleration of the rotor-slip 274
1 3.8 Motor under load 274
1 3.9 Slip and slip speed 274
1 3. 1 0 Voltage and frequency induced in the
rotor 275
1 3. 1 1 Characteristics of squirrel-cage
induction motors 276
1 3. 1 2 Estimating the currents in an induction
motor 277
1 3. 1 3 Active power flow 278
1 3. 1 4 Torque versus speed curve 28 1
1 3. 1 5 Effect of rotor resistance 282
1 3. 1 6 Wound-rotor motor 284
1 3. 1 7 Three-phase windings 285
1 3. 1 8 Sector motor 288
1 3. 1 9 Linear induction motor 289
13.20 Traveling waves 291
13.21 Properties of a linear induction
motor 291
13.22 Magnetic levitation 293
Questions and Problems 295
24. SELECTION AND APPLICATION OF
THREE-PHASE INDUCTION
MOTORS 299
1 4.0 Introduction 299
1 4. 1 Standardization and classification of
induction motors 299
1 4.2 Classification according to environ¬
ment and cooling methods 299XII CONTENTS
15.
1 4.3 Classification according to electrical
and mechanical properties 30 1
25. SYNCHRONOUS GENERATORS 335
1 6.0 Introduction 335
1 4.4 Choice of motor speed 303 16.I Com merc iaI sy nch ronous
1 4.5 Two-speed motors 303 generators 335
1 4.6 Induction motor characteristics under 16.2 Number of poles 335
various load conditions 305 16.3 Main features of the stator 336
I4.7 Starting an induction motor 308 16.4 Main features of the rotor 340
I4.8 Plugging an induction motor 308 16.5 Field excitation and exciters 342
1 4.9 Braking with direct current 309 16.6 Brushless excitation 343
I4.K) Abnormal conditions 310 16.7 Factors affecting the size of
I4. 1 1 Mechanical overload 3 IO synchronous generators 344
26. 1 2 Line voltage changes 3 1 0 I6.8 No-load saturation curve 345
27. 1 3 Single-phasing 310 1 6.9 Synchronous reactance-equivalent
14.I4 Frequency variation 3 1 1 circuit of an ac generator 346
28. 1 5 Induction motor operating as a 16.I0 Determining the value of Xs 348
generator 3ll I6.ll Base impedance, per-unit 349
29. 16 Complete torque-speed characteristic 16. 1 2 Short-circuit ratio 350
of an induction machine 314 16. 1 3 Synchronous generator under
30. 1 7 Features of a wound-rotor induction load 350
motor 3 15 1 6.14 Regulation curves 352
14.18 Start-up of high-inertia loads 3 1 5 I6.15 Synchronization of a generator 353
14.19 Variable-speed drives 315 16.16 Synchronous generator on an infinite
1 4.20 Frequency converter 315 bus 355
Questions and Problems 318 1 6. 17 Infinite bus-effect of varying the
exciting current 355
EQUIVALENT CIRCUIT OF THE 16. 1 8 Infinite bus-effect of varying the
INDUCTION MOTOR 322 mechanical torque 355
1 5.0 Introduction 322 16.19 Physical interpretation of alternator
1 5. 1 The wound-rotor induction motor 322 behavior 357
1 5.2 Power relationships 325 1 6.20 Active power delivered by the
1 5.3 Phasor diagram of (he induction generator 358
motor 326 1 6.2 1 Control of active power 359
1 5.4 Breakdown torque and speed 327 16.22 Transient reactance 359
1 5.5 Equivalent circuit of two practical
motors 327
1 6.23 Power transfer between two
sources 36 1
1 5.6 Calculation of the breakdown
torque 328
1 6.24 Efficiency, power, and size of
electrical machines 362
1 5.7 Torque-speed curve and other
characteristics 329
Questions and Problems 364
1 5.8 Properties of an asynchronous 17. SYNCHRONOUS MOTORS 369
generator 330 17.0 Introduction 369
1 5.9 Tests to determine the equivalent I7.I Construction 370
circuit 33 I 17.2 Starting a synchronous motor 372
Questions and Problems 333 /7.3 Pull-in torque 372CONTENTS xiii
description 372
calculations 373
17.6 Power and torque 376
17.7 Mechanical and electrical angles 377
17.8 Reluctance torque 378
1 7.9 Losses and efficiency of a
synchronous motor 379
17.10 Excitation and reactive power 380
1 7. 1 1 Power factor rating 38 1
17.12 V-curves 382
17.13 Stopping synchronous motors 383
1 7. 14 The synchronous motor versus the
induction motor 385
17.15 Synchronous capacitor 385
Questions and Problems 388
31. SINGLE-PHASE MOTORS 391
18.0 Introduction 39 1
1 8. 1 Construction of a single- phase
induction motor 39I
1 8.2 Synchronous speed 393
1 8.3 Torque-speed characteristic 394
1 8.4 Principle of operation 394
1 8.5 Locked-rotor torque 396
1 8.6 Resistance split-phase motor 396
1 8.7 Capacitor-start motor 398
1 8.8 Efficiency and power factor of singlephase induction motors 399
1 8.9 Vibration of single-phase motors 40 1
I8.10 Capacitor-run motor 402
1 8. 1 1 Reversing the direction of
rotation 403
1 8. 1 2 Shaded-pole motor 403
1 8. 1 3 Universal motor 404
I8. 14 Hysteresis motor 405
32. 1 5 Synchronous reluctance motor 407
1 8. 1 6 Synchro drive 408
EQUIVALENT CIRCUIT OF A SINGLE-PHASE MOTOR
I8.I7 Magnetomotive force distribution 409
1 8. 1 8 Revolving mint’s in a single-phase
motor 4I0
33. 19 Deducing the circuit diagram of a
single-phase motor 411
Questions and Problems 414
34. STEPPER MOTORS 417
1 9.0 Introduction 417
1 9. 1 Elementary stepper motor 4I7
1 9.2 Effect of inertia 4 1 8
1 9.3 Effect of a mechanical load 4I9
1 9.4 Torque versus current 420
1 9.5 Start-stop stepping rate 420
19.6 Slew speed 421
19.7 Ramping 422
19.8 Types of stepper motors 422
19.9 Motor w indings and associated
drives 424
19.10 High-speed operation 427
19.11 Modifying the time constant 428
1 9. 1 2 Bilevel drive 428
19.13 Instability and resonance 434
19.14 Stepper motors and linear drives 434
Questions and Problems 434
PART III. ELECTRICAL AND ELECTRONIC
DRIVES
35. BASICS OF INDUSTRIAL MOTOR
CONTROL 439
20.0 Introduction 439
20.1 Control devices 439
20.2 Normally-open and normally-closed
contacts 443
20.3 Relay coil exciting current 443
20.4 Control diagrams 445
20.5 Starting methods 446
20.6 Manual across-the-line starters 447
20.7 Magnetic across-the-line starters 448
20.8 Inching and jogging 450
20.9 Reversing the direction of
rotation 451
20.10 Plugging 453
20.11 Reduced-voltage starting 454
20.12 Primary resistance starting 454xiv CONTENTS
20.13 Autotransformer starting 458
20.14 Other starting methods 460
20.15 Carn switches 461
20.16 Computers and controls 462
ELECTRIC DRIVES
36. 1 7 Fundamentals of electric drives 462
37. 18 Typical torque-speed curves 463
38. 1 9 Shape of the torque-speed
curve 464
20.20 Current-speed curves 466
20.21 Regenerative braking 467
Questions and Problems 468
39. FUNDAMENTAL ELEMENTS OF
POWER ELECTRONICS 472
21.0 Introduction 472
40. 1 Potential level 472
2 1.2 Voltage across some circuit
elements 474
THE DIODE AND DIODE CIRCUITS
21.3 The diode 475
2 1 .4 Main characteristics of a diode 476
2 1.5 Battery charger with series
resistor 476
2 1 .6 Battery charger with series
inductor 478
21.7 Single-phase bridge rectifier 480
21.8 Filters 48 1
2 1 .9 Three-phase, 3-pulse diode
rectifier 483
2 1 . 10 Three-phase. 6-pulse rectifier 485
2 1. 1 1 Effective line current, fundamental
line current 489
2 1 . 1 2 Distortion power factor 490
2 1. 1 3 Displacement power factor, total
power factor 490
41. 1 4 Harmonic content, THD 49 1
THE THYRISTOR
AND THYRISTOR CIRCUITS
42. 15 The thyristor 492
21.16 Principles of gate firing 492
43. 1 7 Power gain of a thyristor 494
2 1 . 1 8 Current interruption and forced
commutation 495
44. 19 Basic thyristor power circuits 496
2 1 .20 Controlled rectifier supplying a
passive load (Circuit I , Table
2 1 D) 496
2 1.2 1 Controlled rectifier supplying an ac¬
tive load (Circuit 2, Table 2 1 D) 497
2 1 .22 Line-commutated inverter (Circuit 3.
Table 2 ID) 498
21.23 AC static switch (Circuit 4. Table
2 ID) 500
2 1.24 Cycloconverter (Circuit 5, Table
2lD) 501
2 1 .25 Three-phase, 6-pulse controllable
converter (Circuit 6, Table 2 1 D) 502
21.26 Basic principle of operation 503
2 1 .27 Three-phase, 6-pulse rectifier feeding
2 1 .28 Delayed triggering-rectifier
mode 505
21.29 Delayed triggering-inverter mode 507
21.30 Triggering range 508
21.3 1 Equivalent circuit of a
converter 509
2 1.32 Currents in a 3-phase, 6-pulse
converter 5 1 1
2 1.33 Power factor 5 1 1
21.34 Commutation overlap 514
21.35 Extinction angle 514
DC-TO-DC SWITCHING CONVERTERS
21.36 Semiconductor switches 515
2 1 .37 DC-to-DC switching converter 5 1 7
21.38 Rapid switching 519
21.39 Impedance transformation 522
2 1 .40 Basic 2-quadrant dc-to-dc
converter 522
converter 525
converter 526
21.43 Switching losses 528CONTENTS xv
DC-TO-AC SWITCHING CONVERTERS 23. ELECTRONIC CONTROL OF
21.44 Dc-to-ac rectangular wave
converter 529
ALTERNATING CURRENT MOTORS 575
23.0 Introduction 575
2 1 .45 Dc-to-ac converter with pulse-width 23.1 Types of ac drives 575
modulation 530 23.2 Synchronous motor drive using
21.46 Dc-to-ac sine wave converter 532 current-source de link 577
21.47 Generating a sine wave 533 23.3 Synchronous motor and
21.48 Creating the PWM pulse train 534 cycloconverter 580
21.49 Dc-to-ac 3-phase converter 535 23.4 Cycloconverter voltage and frequency
21.50 Conclusion 537 control 580
Questions and Problems 537 23.5 Squirrel-cage induction motor with
cycloconverter 582
ELECTRONIC CONTROL OF DIRECT¬ 23.6 Squirrel-cage motor and static voltage
CURRENT MOTORS 541
22.0 Introduction 54 1
23.7
controller 589
Soft-starting cage motors 590
22.1
22.2
SELF-COMMUTATED INVERTERS
reversal 544 23.8 Self-commutated inverters for cage
reversal 545 23.9 Current-source self-commutated
converters 545
frequency converter (rectangular
wave) 593
with circulating current 546
23.10 Voltage-source self-commutated
frequency converter (rectangular
22.6 Two-quadrant control with positive wave) 594
torque 549 23.11 Chopper speed control of a wound¬
22.7 Four-quadrant drive 549 rotor induction motor 597
22.8
22.9
Six-pulse converter with freewheeling
diode 551
Half-bridge converter 556
23.12 Recovering power in a wound-rotor
induction motor 599
22.10 DC traction 558 PULSE-WIDTH MODULATION DRIVES
22.11 Motor drive using a dc-to-dc
switching converter 560
23.13 Review of pulse-width g’
modulation 602
22.12 Introduction to brushless de
motors 565
23.14 Pulse-width modulation and ind^Hih) – A
motors 604 E :
22.13 Commutator replaced by reversing
switches 566
TORQUE AND SPEED CONTROL
22.14 Synchronous motor as a brushless de
machine 568
OF INDUCTION MOTORS XA4 DE ‘
22.15 Standard synchronous motor and 23.15 De motor and flux orientation 604 1’ A
brushless de machine 569 23. 1 6 Slip speed, flux orientation. agdSn-jQiECA
22.16 Practical application of a brushless de torque 605
motor 569
Questions and Problems 57 1
45. 1 7 Features of variable-speed control¬
constant torque mode 607xvi CONTENTS
46. 18 Features of variable-speed control¬
constant horsepower mode 610
23.19 Features of variable-speed control¬
generator mode 6 1 0
23.20 Induction motor and its equivalent
circuit 61 1
23.2 1 Equivalent circuit of a practical
motor 612
23.22 Volts per hertz of a practical
motor 613
23.23 Speed and torque control of induction
motors 614
23.24 Carrier frequencies 615
23.25 Dynamic control of induction
motors 615
23.26 Principle of flux vector control 616
23.27 Variable-speed drive and electric
traction 618
23.28 Principal components 621
23.29 Operating mode of the 3-phase
converter 622
23.30 Operating mode of the single-phase
converter 624
23.31 Conclusion 629
Questions and Problems 629
PART IV. ELECTRIC UTILITY POWER
SYSTEMS
47. GENERATION OF ELECTRICAL
ENERGY 635
24.0 Introduction 635
48. 1 Demand of an electrical system 635
24.2 Location of the generating station 637
24.3 Types of generating stations 637
24.4 Controlling the power balance
systems 639
24.6 Conditions during an outage 641
24.7 Frequency and electric clocks 642
HYDROPOWER GENERATING STATIONS
24.8 Available hydro power 642
24.9 Types of hydropower stations 643
24.10 Makeup of a hydropower plant 644
24.11 Pumped-storage installations 646
THERMAL GENERATING STATIONS
49. 1 2 Makeup of a thermal generating
station 648
24.13 Turbines 650
24.14 Condenser 650
24.15 Cooling towers 650
24.16 Boiler-feedpump 651
50. 1 7 Energy flow diagram for a steam
plant 651
51. 18 Thermal stations and the
environment 652
NUCLEAR GENERATING STATIONS
52. 19 Composition of an atomic nucleus;
isotopes 655
24.20 The source of uranium 655
24.21 Energy released by atomic fission 656
24.22 Chain reaction 656
24.23 Types of nuclear reactors 657
24.24 Example of a light-water reactor 658
24.25 Example of a heavy-water reactor 659
24.26 Principle of the fast breeder
reactor 660
24.27 Nuclear fusion 661
Questionsand Problems 661
53. TRANSMISSION OF ELECTRICAL
ENERGY 664
25.0 Introduction 664
54. 1 Principal components of a power
distribution system 664
25.2 Types of power lines 665
25.3 Standard voltages 667
25.4 Components of a HV transmission
line 667
25.5 Construction of a line 668
25.6 Galloping lines 669
25.8 Pollution 669
25.9 Lightning strokes 670CONTENTS xvii
25.10 Lightning arresters on buildings 671
25.11 Lightning and transmission lines 671
25.12 Basic impulse insulation level
(BIL) 672
25.13 Ground wires 673
25.14 Tower grounding 673
25.15 Fundamental objectives of a
transmission line 675
25.16 Equivalent circuit of a line 676
25.17 Typical impedance values 676
25.18 Simplifying the equivalent circuit 678
25.19 Voltage regulation and power¬
transmission capability of
transmission lines 680
25.20 Resistive line 680
25.21 Inductive line 681
25.22 Compensated inductive line 683
25.23 Inductive line connecting two
systems 685
25.24 Review of power transmission 686
25.25 Choosing the line voltage 687
25.26 Methods of increasing the power
capacity 689
25.27 Extra-high-voltage lines 689
25.28 Power exchange between power
centers 692
25.29 Practical example of power
exchange 693
Questions and Problems 695
55. DISTRIBUTION OF ELECTRICAL
ENERGY 698
26.0 Introduction 698
i
SUBSTATIONS ‘
26.1 Substation equipment 698 ‘sX; t
26.2 Circuit breakers 698
26.3 Air-break switches 702 de
26.4 Disconnecting switches 702 r ?
26.5 Grounding switches 702
26.6 Surge arresters 702 ‘
26.7 Current-limiting reactors 705
26.8 Grounding transformer 706
26.9 Example of a substation 707
26.10 Medium-voltage distribution 709
56. 1 1 Low-voltage distribution 709
PROTECTION OF MEDIUM-VOLTAGE
DISTRIBUTION SYSTEMS
57. 1 2 Coordination of the protective
devices 714
58. 13 Fused cutouts 7 15
26.14 Reclosers 716
26.15 Sectionalizers 716
26.16 Review of MV protection 717
LOW-VOLTAGE DISTRIBUTION
26.17 LV distribution system 717
26.18 Grounding electrical installations 719
26.19 Electricshock 719
26.20 Grounding of 120 V and 240V/120V
systems 720
26.21 Equipment grounding 721
26.22 Ground-fault circuit breaker 723
26.23 Rapid conductor heating:
I2t factor 724
26.24 The role of fuses 725
26.25 Electrical installation in
buildings 725
26.26 Principal components of an electrical
installation 725
Questions and Problems 727
59. THE COST OF ELECTRICITY 729
27.0 Introduction 729
27.1 Tariff based upon energy 730
\ 27.2 Tariff based upon demand 730
\ 27.3 Demand meter 730
y 27.4 Tariff based upon power factor 732
] 27.5 Typical rate structures 733
: 27.6 Demand controllers 733
.
“i ‘^7.7 Power factor correction 737
27.8 Measuring electrical energy, the
watthourmeter 740
27.9 Operation of the watthourmeter 741
60. 1 1 Measuring three-phase energy and
power 743
Questions and Problems 743xviii CONTENTS
61. DIRECT-CURRENT TRANSMISSION 746
28.0 Introduction 746
28.1 Features of de transmission 746
28.2 Basic de transmission system 747
28.3 Voltage, current, and power
relationships 748
28.4 Power fluctuations on a de line 75 1
28.5 Typical rectifier and inverter
characteristic 752
28.6 Power control 753
28.7 Effect of voltage fluctuations 754
28.8 Bipolar transmission line 754
28.9 Power reversal 755
28.10 Components of a de transmission
line 755
62. 1 1 Inductors and harmonic filters on the
de side (6-pul.se converter) 756
28.12 Converter transformers 756
28.13 Reactive power source 757
28.14 Harmonic filters on the ac side 757
28.16 Ground electrode 757
63. 1 7 Example of a monopolar converter
station 757
28.18 Thyristor converter station 758
28.19 Typical installations 760
Questions and Problems 765
64. TRANSMISSION AND DISTRIBUTION
SOLID-STATE CONTROLLERS 768
TRANSMISSION POWER FLOW CONTROLLERS
29.0 Introduction 768
65. 1 Thyristor-controlled series capacitor
(TCSC) 769
29.2 Vernier control 77 1
29.3 Static synchronous compensator 773
29.4 Eliminating the harmonics 776
29.5 Unified power How controller
(UPFC) 776
29.6 Static frequency changer 780
DISTRIBUTION CUSTOM POWER PRODUCTS
29.7 Disturbances on distribution
systems 782
29.8 Why PWM converters? 784
29.9 Distribution system 785
29.10 Compensators and circuit
analysis 787
66. 1 1 The shunt compensator: principle of
operation 787
67. 1 2 The series compensator: principle of
operation 793
29.13 Conclusion 796
Questions and Problems 797
68. HARMONICS 799
30.0 Introduction 799
30.1 Harmonics and phasor diagrams 799
30.2 Effective value of a distorted
wave 800
30.3 Crest factor and total harmonic
distortion (THD) 801
30.4 Harmonics and circuits 802
30.5 Displacement power factor and total
power factor 804
30.7 Generating harmonics 805
30.8 Correcting the power factor 807
30.9 Generation of reactive power 808
EFFECT OF HARMONICS
30.10 Harmonic current in a capacitor 809
69. 1 1 Harmonic currents in a
conductor 810
30.12 Distorted voltage and flux in a
coil 810
30.13 Harmonic currents in a 3-phase,
4-wire distribution system 812
30.14 Harmonics and resonance 813
70. 15 Harmonic filters 8 1 8
30.16 Harmonics in the supply
network 819
30.17 Transformers and the K factor 821
HARMONIC ANALYSIS
71. 18 Procedure of analyzing a periodic
wave 823
Questions and Problems 827CONTENTS xix
72. PROGRAMMABLE LOGIC
CONTROLLERS 831
31.0 Introduction 83 1
3 1 . 1 Capacity of industrial PLCs 83 1
3 1 .2 Elements of a control system 832
3 1.3 Examples of the use of a PLC 835
3 1 .4 The central processing unit
(CPU) 838
3I.5 Programming unit 838
3 1.6 The I/O modules 839
31.7 Structure of the input modules 839
3 1 .8 Structure of the output modules 840
31.9 Modular construction of PLCs 84 1
3LI0 Remote inputs and outputs 84I
3 1 . 1 1 Conventional control circuits and PLC
circuits 844
73. 1 2 Security rule 847
74. 13 Programming the PLC 847
3I.14 Programming languages 847
3 1 . 15 Advantages of PLCs over relay
cabinets 848
MODERNIZATION OF AN INDUSTRY
3 1 . 16 Industrial application of PLCs 850
75. 1 7 Planning the change 850
76. 1 8 Getting to know PLCs 85 1
77. 1 9 Linking the PLCs 853
31.20 Programming the PLCs 853
31.21 The transparent enterprise 855
Questions and Problems 856
References 859
Appendixes 865
AXO Conversion Charts 865
AX1 Properties of Insulating
Materials 869
AX2 Electrical, Mechanical and
Thermal Properties of Some
Common Conductors (and
Insulators) 870
AX3 Properties of Round Copper
Conductors 871
Problems 877
Index 879A
Acceleration (of a drive system).
78. 59.
Active power. 136. 140. 169,675
ACSR cable. 667. 677
Aerial conductors. 677
Air. 869
Air gap. 85
Alternator. 7 1. 159.335
three-phase (acc Alternator.
3-phase)
two-phase. 160
Alternator. 3-phase, 335-364
brushless excitation of. 343
construction of, 336-340
cooling of, 339
elementary. 159
equivalent circuit, 346
excitation of. 342
historical example. 346
mechanical pole shift. 357
power output. 358. 362
saturation curve. 345
short-circuit ratio. 350
synchronization of. 353
synchronous reactance. 346
synchronous speed. 336. 340
torque angle. 358
Index
transient reactance. 359
voltage regulation. 352
Ambient temperature. 127
Ampacity, 677
Amplitude modulation ratio. 532
Angle. 6
commutation, 514
delay. 505
“effective.” 750
extinction, 514. 750
firing. 750
phase. 22
torque. 359. 376. 377
Anode. 475, 492
Apparent power. 141, 147
Arc furnace. 791
Arcing horns, 702
Armature
of a de generator. 73. 74. 76.
79. 90
of a de motor. 99. 100
reaction. 77, 1 13
Asynchronous generator. 311. 330
Autotransformer. 226-230
variable, 235
Auxiliary winding. 391. 396
B
Back-to-back converters, 747. 760
Base speed. 1 1 6
Basic insulation impulse level.
80. 705
B-H curve. 27
of vacuum. 27
of soft magnetic materials, 28. 29
BIL. 672,705
Billing demand. 734, 735
Bilevel drive, 428
Bipolar line. 754
Bipolar winding. 424
BJT, 472.516
Boiler, 648
efficiency. 647
feed pump, 65 1
Boolean language. 848
Boost chopper, 524
Braking, 463
of a de motor. 109-1 1 1
of an induction motor. 308, 309
of a synchronous motor, 383
regenerative. 3 1 2
time. 1 1 1
Bridge rectifier. 480. 486-489
brownout. 783
Brush. 86. 87
879880 INDEX
Brushless de motor. 569
Brushless excitation. 343. 371
Brush losses. 122
Buck chopper, 519
Bushing. 231,232. 699
C
Cable. 677. 693
impedance of. 677
submarine, 693
Cam switch, 441. 461
CANDU. 659
Capacitance (distributed). 230. 23 1
81. 720
Capacitor, 139. 145
energy in, 25
Carrier frequency. 530. 615
Catenary. 558
Cathode. 475, 492
cemf (see Counter emf)
Central processing unit, 833. 838
Centrifugal switch. 396. 397
Celsius (degree) 5. 7
Chain reaction, 656
Characteristic impedance (see
surge impedance)
Chopper, 5 18-52 1. 558-560
Circuit
equations for. 26
(PLC). 844
solution of, 40-15, 148, 170
three-phase. 158
tw’o-phase. 160, 254
Circuit breakers
air-blast. 700
manual. 439
minimum oil. 700
oil. 699
solid-state. 790, 797
sulfur hexafluoride. 700
vacuum. 701, 702
Circular mil, 866
Clock motor. 406. 642
Coercive force, 32
Coil pitch. 89. 285. 288
Commutating poles. 79. 1 13
Commutation
de machine. 91-93
forced, 495
line. 484
power factor of, 490. 5 1 1
natural, 484 pl. I’NGElW. with freewheeling diode. 55 1
overlap, 5 14, TSO ‘ J 12-pulse, 760
self. 592 F 1R Cn Cooling tower, 650
Commutator, 72, 73^6rj99iQ‘fECA Coordination of protective
Compensating winding, 114 devices, 714
Compensation (line), 683, 688
Compensator
(series), 786. 793
(shunt), 786, 787
Computer control, 831
Condenser, 649, 650
synchronous, (see Synchronous
capacitor)
Appendix AX3)
bundled, 669
gauge number, 87 1
round copper. 87 1
Conjugate (of vector), 151
Consequent poles, 304
Constant horsepower mode, 1 16
Constant torque mode, 116
Contact
normally closed. 443
normally open, 443
self-sealing, 449
(simulated). 833
Contactor
electronic, 500
magnetic, 442
Contingency, 641
Control diagram, 445, 832
Control system, 832
Convection (heat loss by). 63
Conventional current flow, 15
Conversion charts, 8 (see
Appendix AX0)
Converter, 495
dc-to-ac, 529
dc-to-ac, three phase, 535
dc-to-dc. 517, 522, 560
equivalent circuit of, 509
PWM. 784
half bridge, 556
(mercury-arc), 757
Copper loss. 121
Corona effect. 669
Cosine-sine conversion. 20
Counter emf. 96
CPU (see Central processing unit)
Crest factor, 801
Current density, 121
Current transformer, 231-234
Cutout, 715
Cycloconverter, 501. 580, 582
D
Damper winding. 340. 370
DC transmission (see HVDC
transmission)
Delta connection, 167, 169
voltage and current in, 169
Demand, 635, 730
controller. 733
meter, 730
Deuterium, 655
Differential compound, 84. 107
Diode
operation of, 475
properties of, 476
Direct-current
motors. 96
generators, 7 1
Displacement power factor,
490, 512
Distortion
de field. 78, 113
harmonic, 24. 799.810-812,
82. 823
power factor, 490
Distribution systems
disturbances. 782
low-voltage, 709.717, 725
medium-voltage, 709INDEX 88 1
three-phase. 3-wire. 719
three-phase, 4-wire, 718
Disturbances on distribution
systems, 782
Drives (fundamentals of), 57, 462
Drives, electronic
(types of ac), 575
chopper and series motor, 559
converters with circulating
current, 546
(de motor), 560-565
electric traction. 618-625
principles of, 57. 58. 462
cycloconverter, 580. 582. 627
hoist control. 549
induction motor. 582. 587.
592-596
synchronous motor. 577-579
wound rotor motor. 597-602
DSTATCON, 787. 796
Duty cycle. 520, 526
DVR, 796
Dynamic braking, 109
Dynamo, (see generator, de)
E
Eddy currents. 34. 35, 822
Effective value. 20
Efficiency. 53
of de machines. 123-125
of electrical machines. 362
EHV line. 689
Electromagnetic induction. 29
Electronic power circuits
basic types. 496
Electronvolt. 866
Enclosures. 299
Energy. 53
consumed by a city. 738
consumed by appliances. 736
consumed in the U.S., 729
flow in a thermal station. 65 1
in three-phase circuits. 743
measurement of. 740
transformation of, 53
unit of. 7
eV, {see Electronvolt)
Exciter, 342
brushless, 343. 371
‘■pilot. 336
F
Fahrenheit (degree). 61
induction. 29
Fast breeder reactor. 660
Feeder, 705, 727
Field
of a de machine, 85
revolving. 335
Filter. 481,486. 756. 757,818
Firing (see Triggering)
Fission, 656
Flashover, 671, 672. 674, 675
Flux (see Magnetic flux)
Flux orientation. 604. 605
Flux vector control, 616
Force, 50
on a conductor, 3 1
of gravity, 50
unit of. 6
Foucault currents, (see Eddy
currents)
Fourier series analysis (see
Harmonic analysis)
Freewheeling diode, 519. 551
Frequency, 19
Frequency converter. 309, 370.
83. 806
Frequency modulation
ratio, 532
Fuse. 715. 725
Fusion (nuclear), 661
G
Galloping line, 669
Gate. 492
Gear motor. 303
Generator, de, 71-93
compound. 83
, . construction of, 84-90
differential compound, 84
equivalent circuit of. 82
historical note. 89
induced voltage, 75, 76, 80
neutral zone, 76
rating, 84
separately-excited, 82
shunt, 80
voltage, 76
voltage regulation. 84
Generator, ac. (.see alternator)
GFCI. (.see Ground fault circuit
breaker)
Grafcet. 847
Grand Coulee dam. 643
Ground
resistance of, 673
wire, 673, 722
Ground fault circuit breaker, 723
Grounding
of de terminals. 757
of electrical systems, 719
of equipment. 72 1
GTO.472. 516
H
Half bridge converter. 556
Half-step drive. 425
Harmonic analysis, 823-827
Harmonic distortion (.see
Distortion )
Harmonics, 23, 783. 799
analysis of. 823-827
and circuits, 802. 809-812
and phasor diagrams, 799
and transformers. 821
effective value of. 801
elimination of. 776, 790. 8 1 8
filter. 756, 757,818
in a square wave. 25
in an alternator. 337
in power systems. 812. 815.
84. 821
generation of. 805
resonance. 8 1 3-8 16
Heat. 60
conduction of. 62
convection. 63
Heat, continued
(specific), (see Appendix.
Table AX2)
transmission of. 62
Heating
by induction. 237. 739
of electrical machines. 127-130
Heavy water, 655. 659
Hertz. 6
Historical machines. 89. 346
Horsepower. 52
Hot spot temperature. 127
HVDC transmission, 746-765
basic equations, 750
bipolar line. 754
components of. 755
ground electrode, 757
harmonic filter. 756. 757
rectifier and inverter
characteristic, 752-754
scale model. 750
typical converter stations. 757-765
Hydrogen. 655. 869. 870
cooling. 339. 364. 386
isotopes of. 655
Hydropower station. 642-646
power of. 642
Hysteresis, 33
loop, 33
loss, 33
motor. 405
I
1GBT. 472.517
Impedance
of ac circuits, 26. 41, 813
per unit. 215, 216, 349
ratio. 191
transformation. 192, 522
Impulse voltage. 672
Inching. 450
Induced voltage. 183
equality with applied
voltage, 184
Inductance
current in, 36-40
energy in. 25
smoothing, 748, 757
voltage induced in, 36. 183
Inductor (see Inductance)
Inertia
effect of, 58. 418
energy due to. 56
moment of, 54. 56
Infinite bus, 353
Input module. 833, 834, 839
Insulation
classes, 126-128
life expectancy. 126
Insulators
deterioration of. 1 26
pin-type. 667
properties of. 869, 870
suspension-type. 667
Interpole (see Commutating poles)
equivalent circuit of, 5 1 1
line-commutated. 498, 503
self-commutated. 498, 529. 576.
85. 594
I/O modules. 839
Ionization. 669
Iron losses. 33-36. 122
Isotope, 655
J
Jogging, 450
Joule. 6
K
kcmil, 866
K factor, 82 1
Kelvin, 5
Kinetic energy, 54
of linear motion, 54
of rotary motion, 54
Kirchhoff (KVL, KCL), 40. 41
kVA, 141
L
Lagging. 21, 22. 143
Laminations, 36. 203, 265, 338
Lap winding
of a de generator. 75
of a de motor, 100
of an induction motor, 285-288
• of a synchronous machine, 336
Leakage flux, 199, 200, 276
Leakage reactance, 200, 322
Lightning, 670
arresters, 671, 702
surge on a line, 672
Light water, 655
Line voltage, 166
Line commutated (see
Commutation, natural)
Linear induction motor, 289
Linear motion, 59
Limit switch, 442
active. 137. 154
nonlinear. 791
reactive. 138, 154
Lorentz force, 31, 264
Losses
in electrical machines, 120-125
in transmission lines, 676
in transformers, 206, 821
(stray), 821
M
Magnetic
constant, 27
field intensity, 27
flux, 27
flux density, 27-29
levitation, 293
permeability. 28
Magnetomotive force, 27
Mass, unit of, 5
MCM, 838 (see kcmil)
Memory (non volatile), 838
(volatile), 838
Metals, properties of. 842
MeV, (see eV)
Mil. 867
Mil (circular), 866
Mill, 735
Moment of inertia, 56
equations for, 55INDEX 883
MOSFET, 472,517
Motor, direct current. 96-1 1 7
braking, 109-1 1 1
brushless, 565, 568, 569
compound, 106
differential compound, 107
mechanical power, 98
permanent magnet, 117
plugging, 1 10
series. 104-105
shunt, 103. 108
speed control, 100-103, 114
starting of, 97, 108
torque, 98
torque-speed curve, 116
Motor, single-phase induction,
391-414
capacitor-run, 402
capacitor-start. 398
construction of, 391
equivalent circuit, 409-413
mmf distribution, 409
principle of, 394
revolving mmf. 410
split-phase, 396
synchronous speed, 393
torque-speed characteristic.
1. 400
vibration of, 401
Motor, synchronous (see
Synchronous motor)
Motor, three-phase induction,
263-295
abnormal operating conditions, 310
as generator, 305
basic equations. 273-275, 279,
291,306
braking of, 308, 309
construction of, 263-267, 290
direction of rotation. 270
enclosures. 299
equivalent circuit. 323-325,
331,612
(flux orientation in), 605
flux vector control. 616, 619
linear type. 289
mechanical power, 279
plugging of, 308
principle of, 264, 607-610
rotating field, 265
rotor voltage and frequency, 275
sector type, 288
slip, 274, 291
slip speed, 274, 307, 605
standardization of, 299
synchronous speed, 271
torque, 279, 284
torque-speed characteristic, 28 1.
283, 302, 308, 329, 330. 463
two speed, 303
typical characteristics of, 276, 297
variable speed, 465
volts per hertz rule, 613
wound rotor, 264, 284. 315
N
National Electrical Code, 725
Network, 665
Neutral
of single-phase system. 225. 717
of three-phase system, 164, 707,
719,812
zone, 76, 78, 89, 113
Newton. 6, 50
Notation (E, A P), 17, 19, 151,
154, 472
Nuclear
power stations, 654-661
reactors (types of). 657
O
Ohm, 6
Oil (as coolant), 63
Outage, 641
Outlet, 145. 727
power of, 145
Output module, 833, 840
Over-compound generator, 84
P
PAM motor, 305
Pascal, 6
, PCC.(see point of common coupling)
Peak inverse voltage, 476. 486
Penstock, 644
Permeability, 27, 28
of a vacuum. 27
Per unit impedance
of an alternator, 349
of a transformer, 2 15-2 1 7
Per unit system, 9-1 1
Phase
angle, (see Angle)
meaning of, 162
sequence. 174-176
Phasor, 2 1
Pilot exciter, 336
Pilot light, 442
Pitch. 285. 286, 288
PIV, 476
PLC (see Programmable logic
controller)
PLC
industrial application of. 850
security rule. 847
Plugging. 1 10. 308, 453
Point of common coupling, 819
Polarity
of a transformer, 186, 204, 260
of a voltage, 18
mark, 186
Potential
level, 472
transformer, (see Voltage
transformer)
Power, 52
active, 136, 141, 169, 806
angle (see Torque angle)
apparent, 141, 143
factor (.ve^ Power factor)
in ac circuits, 146, 147
in 3-phase circuits. 162
instantaneous, 134, 135, 160. 162
of a motor, 52. 58. 401
of electrical machines. 362
measurement of, 176
mechanical. 52
reactive. 137, 138.806
triangle. 144, 148884 INDEX
Power factor, 143, 169,512, 586
correction, 146, 737, 791. 807
(displacement), 148.490,
512, 804
(distortion), 490
in rate structures, 732
(total), 490, 804
Power generation
hydropower, 642-646
nuclear, 654-662
pumped storage, 646
thermal, 646-654
thermal model, 652
Power transfer, 361
Primary winding, 185
Programmable logic controller,
831-857
Programming language. 847
Programming unit, 834. 838
Prony brake, 53
Properties
of conductors, 870
of insulators. 869, 870
Protective devices, 7 14
Pull-in torque, 372, 407
Pull-out torque, 373, 407
Pulse width modulation. 530-536,
602, 784
Pumped storage, 646
Push button. 441
PWM (see pulse width modulation)
Q
R
emissivity. 65
Ramping. 422
Rate structure. 733
Rating
name plate. 84
nominal, 84
of a de machine, 84
of an alternator, 342, 362
of a transformer, 206
of a synchronous motor, 380
Reactance
leakage, 200,217, 322
Reactive power, 137, 138
without magnetic field, 148,
806, 808
generation of, 808
Reactor
current limiting. 705
line compensating. 691
nuclear, 657
smoothing, 748, 757
Real power (see Active power)
Receptacle, 727
Recloser, 716
bridge, 480. 485
controlled, 494
equivalent circuit, 5 1 1
power factor of, 5 1 1
three-phase. 3-pulse, 483
three-phase, 6-pulse, 485, 503
References. 859
Regenerative braking (see Braking)
Regulating transformer, 709
Relay
(control), 441, 831
exciting current of. 443
(simulated), 833
thermal, 441. 448
time delay, 455. 837
Reluctance
motor. 407
torque, 378
Remanent magnetism, 103
Residual flux density, 32
Residual magnetism, 103
Resilient mounting, 401
Resistance
unit of, 6
ground, 673
Resonance, 813, 816
Rheostat
field, 81, 103
wound-rotor, 284
Ripple, 482, 486
Rotating field
in a three-phase machine. 265
• in a single-phase motor, 395
synchronous speed of, 271
S
Sag, 669, 783
Salient pole. 338
of a de generator, 80
of an alternator, 345
of a transformer, 206
Scanning (of a PLC), 838
Scott connection, 255
SCR (see Thyristor)
Scroll case, 645
Secondary winding, 185
Sectionalizer, 716
Sector motor, 288
Segment (commutator). 72. 87
Self-commutated inverters, 592
Selsyn, (see Synchro drive)
Semiconductor switch, 5 15
Sequential flow chart. 847
Series capacitor (thyristor
controlled). 769
Series compensation, 689. 769
Series motor
de. 104
single-phase. 404
Service factor. 310
Servo (see Synchro)
SFC (see sequential flow chart)
Shock (electric), 719
Short-circuit
of an alternator. 360
of a transformer. 2 1 2. 236
protection (see Protective devices)
ratio, 350
Simulation (of relays), 833
SI units, 4
Siemens, 6, 866
Sign notation
hybrid, 45
positive and negative, 17. 19.
43, 44
voltage, 17INDEX 885
Single-phase to three-phase
transformation, 178
Sine-cosine conversion, 20
Single-phasing, 310
Size of electrical machines, 130, 362
Slew speed, 421
Slip, 274, 291
Slip ring, 72. 264. 267
Slip speed, 274, 307
Snubber. 528
Source
active, 137. 154
definition of. 16. 154
reactive, 138, 154
Specific heat. 61, 870
Speed, of a drive system, 57. 114
Spillway, 644
SSB, 790. 797
Stability, 359, 638, 640
Stabilized-shunt, 1 13
Star connection (see Wye
connection)
Starter
across-the-line, 446
autotransformer, 458
de motor, 108
part winding, 460
primary resistance, 454
reduced voltage, 454
solid-state. 590
wound rotor, 284
wye-delta, 46 1
Start-stop stepping, 420
STATCOM, 773
Static frequency changer, 780
Static switch, 500
Static synchronous compensator, 773
Static var compensator, 237, 691
Stator, 263, 391
Stepper motor, 4 17-434
Stray losses, 821
Substation, 665,698, 707, 710
Submarine cable, 693
Sulfur hexafluoride, 700, 869
Surge diverter, 702 *
Surge impedance. 690. 691
SVC (.s’^ Static var compensator)
Swell, 783
Switch
air-break, 702
centrifugal, 396, 397
disconnecting, 703
grounding. 702
Switching losses, 528
Symbols (electrical diagram), 444
Synchro drive, 408
Synchronization, 353
Synchronous capacitor, 385. 757
Synchronous generator, (see
Alternator)
Synchronous motor (three-phase)
as brushless de machine, 568, 569
braking of, 383
characteristics, 380
construction of. 369-371
equivalent circuit, 375
excitation of, 371. 380
mechanical power, 376
power factor rating. 381
reactive power, 380
starting of, 372
synchronous speed, 371
torque, 376, 378
V-curve, 382
versus induction motor, 385
Synchronous reactance, 346
Synchronous speed
of single-phase motors, 393
of synchronous motors, 371
of synchronous generators, 336
of 3-phase induction motors, 271
Synchroscope. 354
T
Taps, 205
Tariff (see Rate structure)
TCSC, 769
Temperature, 60
ambient, 127
hottest spot. 128
*• rise (seeTemperature rise)
scales, 5, 61
unit of. 5
Temperature rise
by resistance method, 129
of electrical machines, 125-130
of insulation classes, 127. 128
Tera. 866
Tertiary winding, 248, 757
Tesla, 6, 27, 285
THD (see total harmonic distortion)
Thermal generating stations,
646-654
Thyristor, 492
power gain, 494
principle of, 492. 494
properties of. 493
Time constant, 1 1 1
Torque, 51
angle, 358, 373, 376
breakdown, 282, 327
of a drive system, 57, 58
locked rotor. 282, 283
measurement of, 53
pull-in, 372,407
pull-out, 373, 407
pull-up, 282
reluctance, 378
Total harmonic distortion, 491, 801
Transformers
autotransformer. 226
classification of, 208
construction of, 203
(converter), 756
cooling of, 207
(current), 231
distribution, 225
equivalent circuit. 187,202,
209, 217
exciting current. 197
flux in, 185, 199
grounding type, 706. 709
(high-frequency), 238
high impedance type, 236
ideal, 183-195
impedance of. 215-2 1 7
impedance (measurement of). 212
induced voltage, 185
leakage reactance. 200, 202
losses in, 206886 INDEX
Transformers, continued ‘
magnetizing current. 197
parallel operation of. 219
phase shift. 243, 253. 256
polarity of. 186. 204
rating of, 206
ratio. 187. 188. 191
reflected impedance, 191-195
saturation curve. 206
taps, 5
temperature rise, 209
(toroidal), 234
three-phase (see Transformers,
three-phase)
(voltage), 230
voltage regulation. 211
Transformers (three-phase)
autotransformer, 251
delta-delta. 244
delta-wye. 246
open-delta. 248
phase shift in. 243. 253. 256
phase shifting, 256
polarity of, 260
Scott connection, 255
tertiary winding, 248, 757
three-phase to two-phase, 254
voltage regulation, 258
wye-delta, 247
wye-wye, 248
Transient reactance, 359
Transmission lines
de, 746
choice of conductors, 677
components of. 664, 667
dampers. 669
equivalent circuit. 676-678
impedance of. 676
interconnection of, 665
power and voltage of. 680-685
selection of line voltage, 687
submarine, 693
towers. 669, 673, 675
types of. 665
voltage classes, 666

; 7£Transparent enterprise, 855
Traveling wave. 672
Triggering of gate, 492
Triplen, 812
Turbines, 639, 646. 650
Two-speed motor, 303
Two-phase transformation. 254-256
U
Unified power flow controller, 776
Uninterruptible power supply
(see UPS)
Unipolar winding, 425
Units
base, 4, 5
conversion of, 8, 9 (see
Appendix AX0)
derived. 4, 5
in electricity, 8
in magnetism, 8
in mechanics, 7
in thermodynamics. 7
multiples, 7
per-unit system, 9
SI, 4
Universal motor. 404
UPS. 785
UPFC, 776
Uranium. 655
enriched, 655
V
Valve, 748, 761
Var, 137
Varmeter, 137, 143
V-curve. 382
Vector notation, 151
Volt, 7
Voltage
ac, 18, 19
classes, 666
choice of transmission line,
1. 687
effective value, 20, 800
induced. 30, 183
level. 472-474
peak. 18,20,21
peak inverse, 476, 486
Voltage transformer, 230
Volt-second. 36-39, 519
Volts per hertz rule. 613
W
Ward-Leonard system, 101
Watt. 7, 52
Watthourmeter, 740
Wattmeter. 136
Wave drive. 424
Weber, 7, 30
Websites, 863
Weight, (see Force of gravity)
Wheeling (charge), 640
Wire table. 87 1
Work, 51
Wound-rotor motor. 264, 284
as frequency converter. 315
electronic control of, 597-601
starling of, 284
torque-speed curve, 283
Wye connection, 164, 169
voltage and current in. 169
Z
Zero-speed switch, 454

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